The current combustion engines are constituted of a piston linearly moving, and this linear motion is transformed into circular motion by a connecting rod and a crankshaft. This motion which changes direction several dozens or hundreds of times per second is a real problem, well known, which we do not intend to go over again. Hence the idea of trying to design an engine with a piston that would have a circular motion. There is no real answer to that so far, although the interest and the concern are significant.
The only rotary piston engine that has been built in series is the <<Wankel >> engine. However, its defects, which are related to its complexity, have resulted in that it has never really succeeded to impose itself, despite the massive investments in research and development to which it has been repeatedly subjected.
Engines of the same category as the one that will be exhibited here, have been the object of patents: U.S. Pat. No. 1,003,263A(1911), GB 570 776 A (1945), FR 1 489 283 A (1967), U.S. Pat. No. 7,188,602 B1 (2007), and U.S. Pat. No. 5,819,699 A (1998).
None of these engines has been manufactured or has given any follow-up.
None of these patents mentions a passage of fluid from one side of the piston to the other.
Moreover, in patents U.S. Pat. No. 1,003,263A, U.S. Pat. No. 7,188,602 B1 and U.S. Pat. No. 5,819,699 A, the secondary piston, or roller, has a flat elliptical shape contrary to the shape of the roller of the engine exhibited here.
In patent FR 1 489 283 A, the roller remains parallel to itself, while this particular case is excluded here, because considered as ineffective.
The closest concept is described in GB 570 776 A. GB 570 776 A discloses an engine having a different result of the engine exhibited here for at least 2 reasons: the piston and the roller do not rotate at proportional rotational speeds (a gears system with 2 diameters changes the speed ratio during the cycle) and the main piston has a different shape.
In GB 570 776A, no indication is given on the way to obtain the desired geometry, does not demonstrate the existence of a geometric solution to the posed problem, which is far from being evident especially when the tip of the rotary piston is enlarged as is the case. Moreover, the roller has a center angle of 180°, contrary to the solution exhibited here, in which this angle is lower than 180°. It is shown that if this angle is not lower than 180°, in the range of 100° to 160°, the engine has reduced characteristics.
Recall that a mechanical system allowing obtaining a variable volume, allows creating pumps, engines if it is rigid enough. The engine may be an internal combustion engine, or driven by a pressurized fluid.
We will henceforth use the term engine, but it should be understood as heat engine or engine driven by a pressurized fluid (steam, oil, air, etc.), or pump (suction pump, pressure pump, . . . ).